Medion 42" plasma not turn on

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • forgonati
    Member
    • Oct 2010
    • 25

    #1

    Medion 42" plasma not turn on

    Hi guys, i'm new in the forum, i need help with my old plasma. Sorry for my bad english, i'm a hungarian, so be forgiving with me I got this tv from my friend, its a Medion MR5265. I can't found any info on the web from this tv, sadly, but this tv uses the same one PSU, than the Planar PDP42B.

    The problem is, when i turn the tv on with main switch, the red light comes on, so the standby circuit is OK. When i try it turn on with the RC, i hear clicking, the green LED comes on, the red goes off. After 3 sec, i hear clicking again (relays falls) the green LED goes off, and the red comes on, the tv is return to the standby mode.

    The PSU is a Powerwel PW-1450. My opinion is, the PSU goes to the protected mode, bud i don't know, why. I checked the electrolytic caps, they looks good. I checked the output voltages which goes to the other boards, 5V, 5.5V, 15V, 12V, they are present.
    I have no idea, what's wrong. Maybe the input buffer caps? They are 3x 450V 220uF brand SAMWHA. Or the output caps? They are 3x 250V 560uF. I also checked the Vs coil, but i don't see nothing, any bulging, any discoloration.

    Any idea? Any help would be appreciated.
    Last edited by forgonati; 10-29-2010, 04:21 AM.
  • PlainBill
    Badcaps Legend
    • Feb 2009
    • 7034
    • USA

    #2
    Re: Medion 42" plasma not turn on

    Sorry about my poor English, I'm an American.

    There are three possible reasons for these symptoms.

    1. The power supply is unable to produce all the voltages. These include not only the voltages you mentioned, but also Va, Ve, Vs, Vscan, and Vset.

    2. One of the Sustain boards is loading a power supply or in some cases, has blown a fuse.

    3. The small signal board (also called the main miscellaneous board, or the main control board) is unable to produce one of the voltages it requires.

    This has been said many times, pictures help us help you. My signature contains links on taking good pictures and attaching them.

    PlainBill
    For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

    Comment

    • forgonati
      Member
      • Oct 2010
      • 25

      #3
      Re: Medion 42" plasma not turn on

      Thanks for the quick reply.

      I attached some pictures of the PSU, i hope that helps.

      How i can check these voltages (Va, Vs, etc.)? Only with scope?

      I checked all the fuses which i can find, these fuses are all OK. Sadly, i don't have service manual from this model, i can't find anything on the web from this tv

      But i have schematic from the PSU.
      Attached Files

      Comment

      • forgonati
        Member
        • Oct 2010
        • 25

        #4
        Re: Medion 42" plasma not turn on

        UPDATE:

        I uploaded some new pictures, on this board i find 3 broken or missing ceramic caps, it's possible that these caps causes the problem? Or the tv from this should work independently?
        Attached Files

        Comment

        • PlainBill
          Badcaps Legend
          • Feb 2009
          • 7034
          • USA

          #5
          Re: Medion 42" plasma not turn on

          Originally posted by forgonati
          UPDATE:

          I uploaded some new pictures, on this board i find 3 broken or missing ceramic caps, it's possible that these caps causes the problem? Or the tv from this should work independently?
          I think those caps were the victim of another fault. Those are the buffers, a problem on them often results in a failure of the sustain.

          The Va, Ve, Vs, Vscan and Vset voltages are available at the connectors on the power supply. These voltages go the the sustain cards (cards with big heat sinks on either end of the chassis).

          PlainBill
          For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

          Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

          Comment

          • forgonati
            Member
            • Oct 2010
            • 25

            #6
            Re: Medion 42" plasma not turn on

            But these caps looks like they would be damaged because of a physical impact... Look the last picture (C12). I already saw a burned ceramic cap... These caps don't looks burned, or anything... I try replacing these caps, will see what happens.
            These voltages (Vs, Va, etc.) are hunderts (or thousands) of voltages? I measured voltages on the primary side, and the secondary side of the Vs coil, nothing. These big mosfets (Q6, Q7) feeding the 3x big buffer caps, but i don't know, on what kind of frequency? Maybe 50-100kHz... Can i measure them with classic digital multimeter?

            What do you think about "buffers"? These big elektrolythic buffer caps on the PSU? Or what? do you think, the Y sustain board is damaged?

            Anyway, i checked again these voltages on connectors CN809, CN810, CN811. On "15V" i measured 15,2V, on "12V" 12,2V, on "5V" 5,2V, on "5V5" 5,53V. BUT. On the "32V" i measured only 24V. This may cause the problem? Please, check out the schematic of the PSU here:



            THANKS
            Last edited by forgonati; 10-29-2010, 12:25 PM.

            Comment

            • PlainBill
              Badcaps Legend
              • Feb 2009
              • 7034
              • USA

              #7
              Re: Medion 42" plasma not turn on

              Originally posted by forgonati
              But these caps looks like they would be damaged because of a physical impact... Look the last picture (C12). I already saw a burned ceramic cap... These caps don't looks burned, or anything... I try replacing these caps, will see what happens.
              These voltages (Vs, Va, etc.) are hunderts (or thousands) of voltages? I measured voltages on the primary side, and the secondary side of the Vs coil, nothing. These big mosfets (Q6, Q7) feeding the 3x big buffer caps, but i don't know, on what kind of frequency? Maybe 50-100kHz... Can i measure them with classic digital multimeter?

              What do you think about "buffers"? These big elektrolythic buffer caps on the PSU? Or what? do you think, the Y sustain board is damaged?

              Anyway, i checked again these voltages on connectors CN809, CN810, CN811. On "15V" i measured 15,2V, on "12V" 12,2V, on "5V" 5,2V, on "5V5" 5,53V. BUT. On the "32V" i measured only 24V. This may cause the problem? Please, check out the schematic of the PSU here:



              THANKS
              Did you determine WHY 32V was low?

              Why did your friend give the TV to you? Had he tried to repair it or taken it to a serviceman for repair?

              Here are the problems I see at this point.

              32V is low. Either something is wrong with the power supply, or something is overloading the 32V output.

              Caps are damaged. I feel it might be caused by overheating, you say it looks like mechanical damage.

              You are unable to give me voltage readings which might indicate the area of the problem.

              There is no service information on this TV.

              I don't recognize who made the plasma panel.

              With those problems I am unwilling to spend any more time on this.

              PlainBill
              For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

              Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

              Comment

              • Toasty
                Badcaps Legend
                • Jul 2007
                • 4171

                #8
                Re: Medion 42" plasma not turn on

                Please confirm model number MR5265. It's very odd that nothing comes up on a search.

                I concur with PlainBill's statement "32V is low. Either something is wrong with the power supply, or something is overloading the 32V output."

                +32v, +15v, and +12v all come from the same section of the power supply:
                Transformer T2, IC11 (15v), IC12 (12v). Both IC11 & 12 draw from the 32v line.
                Mind you they are simple voltage regulators. As long as the input voltage to them is above their output, and they are not overloaded, they will work and produce the 12v & 15v. So in this instance where the 32v is low, as you measured it at 24v, they will continue to work producing 12 & 15v.

                You could have a problem on the input side to T2. There may not be enough "drive" to the transformer from the PFC+ which is probably around 310v. If this voltage is low, the big caps should be checked. The main cap C2 is 225uF/450v. The 3 PFC caps are C33, 35, and 36 which are 220uF/450v. Check the 18v going to the PWM, IC6.

                There was also a faulty switching diode discovered in this power supply by our member maxxarcade: https://www.badcaps.net/forum/showthread.php?t=8231

                Also, check out his videos:
                http://www.youtube.com/watch?v=keXf05dNdSI
                http://www.youtube.com/watch?v=VHZcxxDsVck

                He points out 4 small caps on that little circuit board that were causing problems in the high voltage side of the power supply. The unit would shut down. Might be worth checking those out. Its right next to the big cap with the yellow label on top of it.

                If everything going backwards checks out, then you need to trace the 32v line and see what is overloading it. Without a schematic, it will be darn tough to figure.

                Finding other sets that use this power supply and then seeing if those service manuals are available, would be one way of seeing what that 32v line is connected to.

                I do agree that the broken ceramic SMD caps look physically damaged, as if someone bumped them when reassembling the boards. The pics show all the larger caps kicked up in the air, like they were peeled up from hitting something. The solder on the edge side is visibly cracked, but the other side appears okay. When they blow off the board from a failure, there is usually some kind of burn, and I don't see that here. Also notice the rub mark on the board right at C4 in the 2nd picture. I would push the big ones back down with a small tool to hold them and then just touch each end with a soldering iron to re-secure them. The little ones will need more patience and you'll need a capacitance meter to measure them to obtain replacements.

                Best of luck!

                Toast

                EDIT: (again) Now I looked again, and I think they got damaged when someone went to re-plug that board into the adjacent sustain board. The board overlaps the edge of the sustain, as evidenced by the connector setback in picture 1 (post 4). A misalignment when reconnecting caused the damage. Yes!!

                It's a good thing! It means that something didn't go bad and cause them to blow out.
                Last edited by Toasty; 10-29-2010, 09:56 PM. Reason: Forgot ceramic caps damage opinion.... old age :)
                veritas odium parit

                Comment

                • forgonati
                  Member
                  • Oct 2010
                  • 25

                  #9
                  Re: Medion 42" plasma not turn on

                  Thanks for the detailed explanation!

                  The model number of the TV is MR 5265. See attached photo. The logic board is from LG, also the plasma panel. The panel model is PDP42WVSN3.

                  So, in the T2 secondary side i measured 24V DC. The IC11 and IC12 produces voltages 15V and 12V, so they are correct. These voltages (also the 24V) going to the multiplexer IC10. Maybe the problem is there, the 24V is too low, so the PSU shuts down. Anyway, the 18V DC in the IC6 is present.

                  Tomorrow i check the primary side of the T2.

                  I checked all of diodes and rectifiers, they are OK. I checked also the output rectifiers, Those are two TO220 ultra fast dual schottky rectifiers, they are OK.

                  I already watched the Maxxarade's videos, and i already changed these 4 small caps, but still nothing

                  Anyway for the PSU i have a schematic, there:



                  These small ceramic caps are physically damaged, tomorrow i check these ceramic caps, and the big electrolythic caps with a capacitance meter, and i try to replace them.

                  THANKS
                  Attached Files
                  Last edited by forgonati; 10-30-2010, 09:24 AM.

                  Comment

                  • forgonati
                    Member
                    • Oct 2010
                    • 25

                    #10
                    Re: Medion 42" plasma not turn on

                    UPDATE:

                    New interesting thing, what i figured out: When i disconnect the Y sustain board from the PSU, so i have connected to the PSU only the Z sustain board, (other boards are connected) the PSU shuts down, and the green LED on the PSU blinks 5x. (would be good to know, what means these blinking codes) But, when i disconnect the Z sustain board, and i connect only theY sustain, the PSU don't shut down, i let it run cca. 30-40 sec, and the PSU don't shut down So maybe the Z sustain is damaged also, and overload the PSU? How can i check the sustain boards or the hybrid IC?
                    And one more thing, i measured the Vs, Vy and Vsetup voltages with the old analog multimeter (digital is too slow) in those connectors i have cca. 100V AC. This is correct?

                    Thanks
                    Attached Files
                    Last edited by forgonati; 10-30-2010, 09:51 AM.

                    Comment

                    • Toasty
                      Badcaps Legend
                      • Jul 2007
                      • 4171

                      #11
                      Re: Medion 42" plasma not turn on

                      There should be a label somewhere with those correct voltages.

                      Also, when you pull those connectors (Y & Z), monitor the 32v line and see if it rises.
                      veritas odium parit

                      Comment

                      • forgonati
                        Member
                        • Oct 2010
                        • 25

                        #12
                        Re: Medion 42" plasma not turn on

                        I have already tested the PSU without any other panels connected, and in the 32V connector i measured 24V, so the problem is on the PSU. Tomorrow i sheck the voltages on the primary side of the T2.

                        Sadly, i don't see any label with correct Vs, Vy, Vset voltages. So i don't know, these voltages what i measured, are correct or no.

                        What is your opinion about my last post? When i connect only the Y sustain, the PSU don't shut down. How can i test the Y and Z panel, or those hybrid ICs?

                        Thanks
                        Last edited by forgonati; 10-30-2010, 10:49 AM.

                        Comment

                        • PlainBill
                          Badcaps Legend
                          • Feb 2009
                          • 7034
                          • USA

                          #13
                          Re: Medion 42" plasma not turn on

                          The first picture shows 5 labels at the top of the panel. Three of them appear to be warning labels (red). The other two labels are above the Y-Sustain and the power supply. What is on them?

                          The Va Ve Vs, Vscan, Vsetup voltages should be DC. I saw a rapidly pulsing voltage on one once, it was a shorted Y-sustain card.

                          PlainBill
                          For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                          Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                          Comment

                          • forgonati
                            Member
                            • Oct 2010
                            • 25

                            #14
                            Re: Medion 42" plasma not turn on

                            You're right, i found the label, contains those voltages. Thank's a lot. See attached pic. I check those voltages one more time.
                            Attached Files
                            Last edited by forgonati; 10-30-2010, 11:22 AM.

                            Comment

                            • forgonati
                              Member
                              • Oct 2010
                              • 25

                              #15
                              Re: Medion 42" plasma not turn on

                              So, I checked those voltages. When i have connected all boards to the PSU, the PSU shut down after 2 sec, and i don't have enough time for testing, even with an old analog multimeter.

                              BUT. When i disconnect the Z sustain board, the PSU is working properly, and all voltages are present. On the "Vs" i measuring 175V, on "Vsetup" 221V, on "Va" 75,2V, on "-Vy" -80,3V. So all voltages are correct (except the 24V) But only, when i disconnecting the Z sustain board... What now??? I have a shorted Z sustain?
                              Last edited by forgonati; 10-30-2010, 12:03 PM.

                              Comment

                              • PlainBill
                                Badcaps Legend
                                • Feb 2009
                                • 7034
                                • USA

                                #16
                                Re: Medion 42" plasma not turn on

                                Originally posted by forgonati
                                So, I checked those voltages. When i have connected all boards to the PSU, the PSU shut down after 2 sec, and i don't have enough time for testing, even with an old analog multimeter.

                                BUT. When i disconnect the Z sustain board, the PSU is working properly, and all voltages are present. On the "Vs" i measuring 175V, on "Vsetup" 221V, on "Va" 75,2V, on "-Vy" -80,3V. So all voltages are correct (except the 24V) But only, when i disconnecting the Z sustain board... What now??? I have a shorted Z sustain?
                                Yes, you have a shorted Z-sustain. Looking at the first picture, you have an early LG Electronics plasma panel.

                                Search for (Google) the following numbers, they are the numbers of documents on Scribd. I believe the documents will provide information on the panel.

                                Scribd 7580885

                                Scribd 13287511

                                Scribd 19532668

                                You MAY have a shorted hybrid on the Z-Sustain. There should be a part number that begins with 6871

                                PlainBill
                                For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                                Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                                Comment

                                • Toasty
                                  Badcaps Legend
                                  • Jul 2007
                                  • 4171

                                  #17
                                  Re: Medion 42" plasma not turn on

                                  Ok, I got lost between you two. Is the 32v back or not...?

                                  Does "When i disconnect the Z sustain board, the PSU is working properly, and all voltages are present." mean that the 32v is there when the Z is disconnected? You say -present- but don't say -correct-.

                                  The statement after that makes it more confusing-
                                  "So all voltages are correct (except the 24V) But only, when i disconnecting the Z sustain board..."

                                  If yes, the 32v is there when Z is disconnected, then I got it.
                                  If no, then I'm lost.



                                  Toast
                                  veritas odium parit

                                  Comment

                                  • forgonati
                                    Member
                                    • Oct 2010
                                    • 25

                                    #18
                                    Re: Medion 42" plasma not turn on

                                    No, the 32V is still missing, i have only 24V on the "32V" connector. When i disconnect the Z sustain, i still have only 24V. But, when the Z sustain is not connected, the PSU is working perfectly, and i have all voltages, 5V, 5.5V, 15V, 12V, and i have the Vs, Va, Vy and Vsetup voltages also. And the PSU is working. The "32V" is still 24, but i think, the problem is on Z sustain board, probably i have a shorted hybid IC.

                                    Tomorrow i check the PSU one more time, for the missing 32V, but i think, the biggest problem is, the Z sustain card overload the PSU, and send it to the protect mode... I think i must bouhgt a new board, or rebuild the shorted hybrid IC...
                                    Last edited by forgonati; 10-30-2010, 05:16 PM.

                                    Comment

                                    • Toasty
                                      Badcaps Legend
                                      • Jul 2007
                                      • 4171

                                      #19
                                      Re: Medion 42" plasma not turn on

                                      Okay. Then I don't understand how this means a bad Z board. If 32v is not fully up, even when everything is disconnected, then some under volt protection is probably shutting the unit down.

                                      Toast
                                      veritas odium parit

                                      Comment

                                      • forgonati
                                        Member
                                        • Oct 2010
                                        • 25

                                        #20
                                        Re: Medion 42" plasma not turn on

                                        I don't know, really. The "32V" is only 24V, so something is wrong on the PSU, you're right.

                                        But when i disconnect the Z sustain, the PSU is working without any problem, but when i connect it, the PSU is shut down immediately. So probably the biggest problem is on the Z sustain. Tomorrow i check the T2 primary side, and i replace those damaged ceramic caps. And i will see, what's happen.

                                        Comment

                                        Related Topics

                                        Collapse

                                        • pajdek
                                          Lenovo Y700-17ISK turn on and off
                                          by pajdek
                                          Hello, i have some issues with my laptop Lenovo Y700-17ISK (motherboard BY511 NM-A541), it started when i turn on the laptop, but the lcd wont turn on, i then connected it via hdmi to tv and screen was ok. So i thought maybe lcd stripe is faulty, i removed the bottom cover, disconnected main battery, reset the cmos by disconnecting battery for 1 min, then slighty move the lcd stripe. Conncted power supply and tuned on my laptop, the lcd turn on, it started to load os, then it turn off, after a second it turn on, then after like 3 seconds turn off again, and so on. Removed power supply, waited...
                                          09-20-2023, 02:49 AM
                                        • BlackBeetle
                                          MEDION AKOYA S15450 MD 63650 MSN: 30030203
                                          by BlackBeetle
                                          Hello, I have a problem with a Medion notebook.

                                          https://www.medion.com/de/service/pr...etail/30030203

                                          MEDION AKOYA S15450 (MD 63650) A-DE N MSN: 3003 0203 with Windows 10 64x


                                          The keyboard makes random entries and I don't seem to be the only one. Someone on this board has the same problem. I had BIOS version 207 installed and the BIOS version that Medion Support offers here as 209.

                                          https://community.medion.com/t5/Note.../104097/page/2

                                          Bios Version...
                                          08-09-2024, 05:50 PM
                                        • RdeveLabs
                                          MSI GF63 THIN 11UCX (MS-16R6) LAPTOP WON'T TURN ON AFTER RESTARTING
                                          by RdeveLabs
                                          To all the members here...

                                          Let me tell you a little bit about what happened to my laptop (MSI GF63 THIN 11UCX model: MS-16R6) that “maybe” you know how to solve this problem.

                                          So before this problem happened, my laptop was running smoothly. When I wanted to restart my laptop, it looked fine at first. But after I waited for this restart process to take a long time, until finally I panicked (because the restart process did not finish plus the laptop screen only showed a black screen), I immediately pressed and held the power button to force the laptop to turn off. But...
                                          05-05-2025, 04:59 AM
                                        • reessi
                                          Acer Alienware Nitro 5 (GH51G LA-L181P Rev: 1C) & Dell Alienware M15 (GDP50 LA-k452P Rev:1) - Both Shorted PCH (SRKMA)!
                                          by reessi
                                          Hello:

                                          I have both these laptops that appeared to have the same fault so I thought I would have a go at replacing the PCH as something to learn, they both are using the same PCH.


                                          I started on the ACER:

                                          Up on connecting power no signs of life but current is consumed from the bench power supply and the PCH is hot.
                                          All the caps on the top of the PCH are showing 0 ohms and the 3.3v rail is shorted.

                                          I followed the videos from Sorin, Electronics Repair School on Youtube heating from the bottom to install. I practised on around 10 scrap...
                                          10-29-2024, 11:31 AM
                                        • canadaboy25
                                          LG 50PJ550 Plasma tries to turn on then turns off
                                          by canadaboy25
                                          Hey guys,
                                          I have a LG 50PJ550 plasma that will not power on.
                                          When plugged in, the relays click and the screen lights briefly before the relays click again and it shuts right down. It then tries starting up again before giving up and just sits there with the red LED on. Pressing the power button again repeats the process.

                                          During the moment where the screen is on, there is a slight fuzz that starts to go away as most plasma's do when they turn on. So i do not think it is a panel issue as I get a normal looking image for a split second.

                                          I have tested the...
                                          11-17-2020, 11:20 PM
                                        • Loading...
                                        • No more items.
                                        Working...